Hey,

Du be one of prestigious university of India and therefore usually keep their percentage high. Your percentage be very low to secure seat in du for any courses. Also du gives admission on the basis of your best four percentage and not on your aggregate. Even being an obc candidate it won't fetch you a seat with this low percentage. The admissions in du ain't done on the basis of your board and hence it hardly matters if you're an isc or a  cbse student. 

Hope this is understood.